I recently purchased two UPS modules for my Raspberry Pi2 devices that run my home automation system and have been very pleased with them. I have no relationship with the company, just very pleased with their product and has effectively solved any data corruption issue I had where I need to write logs etc. With the 1000mA battery the Pi can run for quite a few hours without power too.
They do a couple of versions with different battery capacities, the product is the UPS PiCo and their website is: www.pimodules.com/index.html
Re: Pi UPS
Thanks for the recommendation, as I was just looking for such a solution.